从入门到入土：基于C语言采用UDP协议实现通信功能的程序

2022-03-04 20:24:11

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基于C语言采用UDP协议实现通信功能的程序

实验目的
- 客户端要求
- 服务器端要求
实验环境
实验代码
功能检验
实验结果

实验目的

客户端要求

客户端可多次向服务器发送数据；
客户端能够接收服务器端发送数据，并回显正确；

服务器端要求

运行端口可配置
将客户端发送来的消息正确显示，并将该消息发送给客户端；
支持多个客户端同时发送

实验环境

vm下Seed Ubuntu
C语言

实验代码

客户端

/**********************************************************\
*                                                         *\
*  program name:tcpclient.c                               *
*  Author:Liang gang & Hu Xiao-qin                        *\
*  Funtion:This program is just a demostrate program      *\
*          to tell students how to use socket to          *\
*          make a tcp communation.                        *\
*  Date: 03-06-2009                                       *\
*                                                         *\
***********************************************************/

#include<stdlib.h>
#include<stdio.h>
#include<sys/socket.h>
#include<netdb.h>
#include<string.h>
#include<unistd.h>
#include<netinet/in.h>
#include<arpa/inet.h>

int main(int argc,char** argv)
{
	struct sockaddr_in server;
	int ret;
	int len;
	int port;
	int sockfd;
	int sendnum;
	int recvnum;
	char send_buf[2048];
	char recv_buf[2048];

	if ((2>argc)|| (argc >3))
	{
		print_usage(argv[0]);
		exit(1);

	}

       if (3==argc) 
       {
		port = atoi(argv[2]);
       }

    if (-1==(sockfd=socket(AF_INET,SOCK_DGRAM,0)))
	{
	perror("can not create socket\n");
	exit(1);
	}

	memset(&server,0,sizeof(struct sockaddr_in));
	server.sin_family = AF_INET;
	server.sin_addr.s_addr = inet_addr(argv[1]);
	server.sin_port = htons(port);

	if (0>(ret=connect(sockfd,(struct sockaddr*)&server,sizeof(struct sockaddr))))
	{
	perror("connect error");
	close(sockfd);
	exit(1);
	}

	len=sizeof(struct sockaddr);

	while(1)
	{
		
		memset(send_buf,0,2048);
		memset(recv_buf,0,2048);

		printf("what words do  you want to tell to server:\n");
		gets(send_buf);

   
		if (0>sendto(sockfd,send_buf,strlen(send_buf),0,(struct sockaddr*)&server,len))
		{
			perror("send data error\n");
			close(sockfd);
			exit(1);
		}

		if (0>(recvfrom(sockfd,recv_buf,sizeof(recv_buf),0,(struct sockaddr*)&server,&len)))
		{
			perror("recv data error\n");
			close(sockfd);
			exit(1);
		}
	
		printf("the message from the server is:%s\n",recv_buf);
		
	}
	close(sockfd);

}

服务端

/**********************************************************\
*                                                         *\
*  program name:tcpserver.c                               *
*  Author:Liang gang & Hu Xiao-qin                        *\
*  Funtion:This program is just a demostrate program      *\
*          to tell students how to use socket to          *\
*          make a tcp communation.                        *\
*  Date: 03-06-2009                                       *\
*                                                         *\
***********************************************************/

#include<stdlib.h>
#include<stdio.h>
#include<sys/socket.h>
#include<netdb.h>
#include<string.h>
#include<unistd.h>
#include<netinet/in.h>
#include<arpa/inet.h>



int main(int argc,char** argv)
{
	struct sockaddr_in server;
	struct sockaddr_in client;
	int length;
	int sockfd;
	int port;
	int connectd;
	int sendnum;
	int recvnum;
	char send_buf[2048];
	char recv_buf[2048];

	if ((1>argc)|| (argc >2))
	{
		print_usage(argv[0]);
		exit(1);

	}

       if (2==argc) 
       {
		port = atoi(argv[1]);
       }



	
	if (-1==(sockfd=socket(AF_INET,SOCK_DGRAM,0)))
      {
	 	perror("create socket error\n");
	 	exit(1);
      }
      
    memset(&server,0,sizeof(struct sockaddr_in));
    server.sin_family = AF_INET;
    server.sin_addr.s_addr = htonl(INADDR_ANY);
    server.sin_port = htons(port);
	length = sizeof(struct sockaddr_in);

    if (-1==bind(sockfd,(struct sockaddr *)&server,sizeof(struct sockaddr)))
    {
    	
	perror("bind error\n");
	exit(1);

    }


    while (1)
	{
		
    memset(send_buf,0,2048);
	memset(recv_buf,0,2048);
        
    if (0>(recvnum = recvfrom(sockfd,recv_buf,sizeof(recv_buf),0,(struct sockaddr*)&client,&length))<0)
		{
		perror("recv error\n");
		close(sockfd);
		exit(1);
		}

	printf ("the message from the client is: %s\n",recv_buf);
	printf ("the message send to the client is: %s\n",recv_buf);

    if (0>(sendto(sockfd,recv_buf,strlen(recv_buf),0,(struct sockaddr*)&client,length)))
		{
		perror("error occar in sending data\n");
		close(sockfd);
		exit(1);
		}

   }

   close(sockfd);
}